Initiation of Detonation

Abstract

A conventional shock tube modified so as to prevent local early detonation from the diaphragm burst or from wall crevasses was used to study the initiation of detonation behind the reflected shock wave. Three types of initiation behavior were observed, two of which appear to be nicely one dimensional. In all cases stoichiometric hydrogen‐oxygen mixtures diluted with argon were used in the tube. In the first case a simple acceleration of the reflected shock occurred when the pressure wave generated by the adiabatic explosion reached the reflected shock. In the second case a typical accelerating wave pattern headed by a shock wave was formed behind the reflected shock while in the third case (which does not appear to be strictly one dimensional) the adiabatic explosion quickly produced a Chapman‐Jouguet detonation wave behind the reflected shock wave. A simple qualitative theory for the occurrence of the wave patterns observed is presented and the adiabatic explosion delays are compared to Schott and Kinsey's recent results using a different shock‐tube technique.